Formosan Journal of Surgery

: 2021  |  Volume : 54  |  Issue : 5  |  Page : 196--199

Primary pleomorphic leiomyosarcoma of descending mesocolon

Suhaildeen Kajamohideen, Balasubramanian Venkitaraman, Sathyanarayanan M Shivkumaran, Prithviraj Premkumar 
 Department of Surgical Oncology, Sri Ramachandra Medical College and Research Institute, Chennai, Tamil Nadu, India

Correspondence Address:
Suhaildeen Kajamohideen
Department of Surgical Oncology, Sri Ramachandra Medical College and Research Institute, Chennai, Tamil Nadu


Mesenteric tumors range from benign cysts to aggressive malignancies and pose both diagnostic and therapeutic challenge. Leiomyosarcomas are rare tumors of the digestive tract comprising <0.1% of colorectal tumors. Similarities between mesenchymal tumors of the digestive tract make histological diagnosis difficult. We report a case of 53-year-old female diagnosed with leiomyosarcoma of descending mesocolon, who has undergone surgery following neoadjuvant chemotherapy and has been on regular follow-up for 2 years. This case signifies the diagnostic difficulties encountered in these rare tumors with a review of the literature.

How to cite this article:
Kajamohideen S, Venkitaraman B, Shivkumaran SM, Premkumar P. Primary pleomorphic leiomyosarcoma of descending mesocolon.Formos J Surg 2021;54:196-199

How to cite this URL:
Kajamohideen S, Venkitaraman B, Shivkumaran SM, Premkumar P. Primary pleomorphic leiomyosarcoma of descending mesocolon. Formos J Surg [serial online] 2021 [cited 2022 Jan 16 ];54:196-199
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Leiomyosarcomas are aggressive tumors of smooth muscle cells commonly seen in uterine, gastrointestinal and soft tissue origin. Differentiation between leiomyosarcoma from gastrointestinal stromal tumors (GISTs) is only possible after the advent of immunohistochemistry (IHC) and many GIST in the past may have been mistakenly labeled as leiomyosarcoma. Primary leiomyosarcoma of mesentery and mesocolon is rare tumors with aggressive behavior. Origin from smooth muscles of the blood vessels has been suggested. Common sites are ileal mesentery followed by transverse and sigmoid mesocolon. The occurrence of primary mesocolic leiomyosarcoma is extremely rare and very few cases have been reported.

 Case Report

This patient, a 53-year-old female with no comorbid illness, was evaluated for lower abdominal pain and abdominal mass. A diagnosis of a retroperitoneal tumor possibly a pedunculated fibroid was made at another hospital. She was taken in for surgery. Intraoperatively, the tumor was found in retroperitoneal plane at the left lumbar region infiltrating the descending and sigmoid colon. Hence, the tumor was deemed in-operable and the patient was referred to our institute.

Preoperative images were reviewed and showed a lobulated heterogeneously enhanced mass in the left abdominopelvic region, displacing the small bowel loops superiorly, suspicious involvement of descending colon [Figure 1]. Trucut biopsy of the tumor showed atypical pleomorphic cells with many giant cells and mitosis of 12/10 hpf [Figure 2]. IHC staining was positive for vimentin, smooth muscle actin, focally positive for desmin, negative for S-100, CD117 and DOG-1, and Ki-67 of 20%, suggestive of a leiomyosarcoma [Figure 2]. The patient received three cycles of neoadjuvant chemotherapy with gemcitabine and paclitaxel. Reassessment with positron emission tomography computed tomography scan showed stable disease without signs of distant metastasis [Figure 1].{Figure 1}{Figure 2}

On laparotomy, the mass was found within the descending mesocolon, encasing the vessels with restricted mobility and feeder vessels from the left gonadal vessels. An extended left hemicolectomy was done and colorectal continuity was restored. The patient had an uneventful postoperative recovery.

Postoperative histopathological examination showed an 11.2 cm × 9.4 cm globular encapsulated mass. Cut surface showed a solid gray white mass with gray-black areas, pleomorphic grade III leiomyosarcoma with 40% necrosis. Margins were free.

The patient completed six cycles of chemotherapy postoperatively followed by adjuvant radiation and is disease-free on year-2 of regular follow-up.


Primary tumors arising from mesentery and mesocolon are rare. The most common tumors are lymphoma followed by mesenchymal tumors. Majority of the mesenchymal tumors are benign. Mesenchymal malignant tumors arise from stromal tumors such as leiomyosarcoma, liposarcoma, fibrosarcoma, and undifferentiated sarcomas. In our case, the biopsy was done preoperatively as it had been deemed inoperable elsewhere.

Mesenteric leiomyosarcoma in an adult was firstly described by Yannopoulos and Stout et al.[1] These tumors are seen in the middle age group with a female predisposition. The proliferation of smooth muscle in response to estrogen has been suggested for this predisposition. They frequently present with abdominal mass or distension followed by pain. Infrequent presentations are abscess, intraperitoneal hemorrhage, or ileus. Most of the tumors attain a large size before becoming symptomatic since the mobility and elasticity of the mesentery allow tumors to occupy a large intra-peritoneal space without causing any obstructive symptoms. The sizes of the reported cases of mesocolic leiomyosarcoma range between 14 and 20 cm [Table 1].{Table 1}

Since 1998, when Hirota et al. demonstrated the expression of c-KIT proto-oncogene in GIST. IHC study is essential for the diagnosis of leiomyosarcoma and to differentiate it from GIST.[9] Before 1998, several GIST haves been misclassified as leiomyosarcoma, and thus overestimating the number of cases of leiomyosarcoma.

Ranchod and Kempson showed the frequency of mitoses to be the most useful indicator of malignant potential.[10] Other prognostic factors include the size and grade of the lesion. The overall prognosis of these tumors is dismal, with 5-year survival between 20% and 30%.[11] Complete primary surgical resection with negative margins is critical for achieving the best outcome.[11]

This patient received neoadjuvant chemotherapy, as she was deemed inoperable and received gemcitabine and docetaxol. The use of neoadjuvant chemotherapy is not well established in leiomyosarcoma. These drugs are used as an extrapolation of the efficacy of these drugs in uterine leiomyosarcoma and soft tissue sarcoma by the French sarcoma study group.[12],[13],[14] Neoadjuvant chemotherapy is aimed to improve negative resection margin and determine the response of tumor to chemotherapy. There is high incidence of metastatic disease, as seen in five out of eight patients in our review of mesocolon leiomyosarcoma and adjuvant chemotherapy may be considered for added benefit. The role of adjuvant radiation after complete resection is of limited value and is considered in selected cases targeting defined anatomical boundaries presumed to be at higher risk, thereby delaying any local recurrence.

Guidelines for adjuvant management of mesocolic or mesenteric leiomyosarcoma are unclear, probably due to the small number of cases reported.


Mesocolic tumors pose a diagnostic and therapeutic challenge. Although surgery is the main modality of treatment, recurrences are frequent. Early detection and surgical resection will improve the prognosis of this type of lesion.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, patient has given consent for her images and other clinical information to be reported in the journal. The patient has given her name and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.


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